Raiders QB Carson Palmer out after taking shot to the back from Panthers DE Greg Hardy

Raiders quarterback Carson Palmer has left Sunday's game against the Carolina Panthers after taking a shot to his back from defensive end Greg Hardy.

Matt Leinart replaced Palmer.

Palmer was flushed the pocket, rolled to the right and stopped to set up. That's when Hardy came barreling in from behind and hit Palmer in his lower back with the crown of his helmet. Officials flagged Hardy for unnecessary roughness because he led with his helmet, resulting in a 15-yard penalty and an automatic first down.

Palmer has been taken to the locker room for observations. He walked there under his own power. His return is uncertain.